Interstitial cystitis (IC), or non-bacterial cystitis, is a vaguely defined chronic inflammatory bladder uroepithelial syndrome responsible for a debilitated lifestyle in up to 450,000 patients in the U.S., 90% of which are women. Urologic diagnosis of IC currently requires invasive procedures such as cystoscopy or a direct bladder biopsy for evidence of either glomerulations or Hunner's ulcers. There exists no clinical consensus model for IC etiology, which is reflected by the critical lack of a useful laboratory test for definitive diagnosis and therapeutic monitoring response. In this Phase I study, it is proposed to develop, conducive to a commercial service laboratory environment, a reproducible semi-automated ultrasensitive ELISA immunoassay for soluble urine specimens and evaluate its diagnostic validity for IC using urine samples from a defined clinical population. Assay basis will involve quantitation of antiproliferative factor immunoreactivity associated with a soluble low molecular weight urine putative antiproliferative factor as applied to in vitro-cultured cells. The studied populations will entail IC patients defined by NIDDK criteria, as well as diagnosed non-IC urine specimens from gynecological and urologic patients whose symptoms mimic IC. Assay results will be statistically analyzed to yield sensitivity, specificity, positive predictive values and negative predictive values for these defined patient populations. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE